Anadara ovalis, or the blood ark clam, is a clam in the family Arcidae. It can be found along the Atlantic coast of North America, ranging from Massachusetts to the West Indies and Brazil. It resides from the low-tide line to a depth of ten feet. The blood ark clam is often noted for its appearance, for it usually can be found two-thirds covered by Periostracum, or dark brown fur. It also noted for its red blood, which is a result of it containing hemoglobin; this makes it different from the majority of mollusks and earned it its name. The size of it typically is between one and three inches.